Mulligans
General Mulligans
Best cards to mulligan for are Hanar and Private Eye. Astalor is the primary long-term win condition, and should be kept except against aggro. All secrets and most of the spells should be tossed, with the exception of preparation and bone spike (prep+bone spike is also an important ramp combo). The bounce spells (shadowstep/breakdance/cheat death/bounce around) can also be kept if you also have a Hanar/Private Eye/Astalor. Elven minstrel is extremely good for bailing out bad draws, if you have a cheap activator for it.